Essential Oil Composition of Three Sideritis Species Used as Herbal Teas in Turkey

The essential oil components present in the aerial parts of S. condensata, S. pisidica and S. perfoliata were investigated by GC and GC-MS. The oil yields of air-dried plants obtained by hydro-distillation were 0.05, 0.08 and 0.08% (v/w), respectively. Eight compounds representing an amount of 83.8% of S. condensata essential oil were identified. The main substances were carvacrol (34.8%), germacrene D (12.5%), ?-pinene (12.1%) and ?-caryophyllene (7.2%). Fourteen constituents represent 77.0% of the S. pisidica essential oil, of which ?-bisabolol (30.2%), sabinene (10.6%), ?-pinene (9.3%) and ?-caryophyllene (7.3%) possess highest concentrations. In the essential oil of S. perfoliata, ten components were identified, comprising 79.7% of the total amount. Here ?-bisabolol (50.7%), ?-caryophyllene (6.9%), myrcene (4.5%) and germacrene D (4.5%) were found to be the major constituents. All volatile substances identified by GC-MS are related to monoterpene or sesquiterpene hydrocarbons.